The present disclosure relates generally to liquid-liquid separation and more particularly to an oil and water separation system using a membrane.
Separation of oil from water has been a longstanding concern. Various devices have been tried but often with mediocre results. Hydrocyclones are generally known but none which circulate the oil/water mixture between membranes or which utilize various advantageous membrane characteristics. Exemplary conventional devices are disclosed in the following: U.S. Pat. No. 7,569,671 entitled “Method and System for Corn Fractionation” which issued to Cheryan on Aug. 4, 2009; U.S. Pat. No. 6,210,575 entitled “Crossflow Filter Cyclone Apparatus” which issued to Chase et al on Apr. 3, 2001; and U.S. Patent Publication No. 2002/0189807 entitled “Method and System for Oil and Water Separation Utilizing a Hydrostatic Pressure Head for Disposal of Water;” all of which are incorporated by reference herein.
In accordance with the present invention, a separation system includes at least a hydrocyclone and one or more membranes. In another aspect, a separation system includes one or more asymmetric membranes (i.e. membranes with a spatial gradient of pore size). A further aspect of a separation system includes an inner membrane, an outer membrane and a hydrocyclonic flow of the feed between the membranes. In yet another aspect of a separation system, separated oil and/or hydrocarbon is removed from adjacent a bottom or tail end of a lumen of a porous hollow fiber or a ceramic membrane. A method of separating oil from water in a mixture is also provided.
The present separation system is advantageous over conventional devices in that the present system is expected to more efficiently and completely perform separation, reduce fouling, and be more cost effective in use. The present system advantageously benefits from a synergistic combination of a hydrocyclone with multiple membranes and/or specific membrane characteristics to simultaneously separate oil-in-water dispersions into oil and water phases. Additional advantages and features of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.